Work function tuning of plasma-enhanced atomic layer deposited WCxNy electrodes for metal/oxide/semiconductor devices

Oren Zonensain, Sivan Fadida, Ilanit Fisher, Juwen Gao, Kaushik Chattopadhyay, Greg Harm, Tom Mountsier, Michal Danek, Moshe Eizenberg

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10 Scopus citations

Abstract

One of the main challenges facing the integration of metals as gate electrodes in advanced MOS devices is control over the Fermi level position at the metal/dielectric interface. In this study, we demonstrate the ability to tune the effective work function (EWF) of W-based electrodes by process modifications of the atomic layer deposited (ALD) films. Tungsten carbo-nitrides (WCxNy) films were deposited via plasma-enhanced and/or thermal ALD processes using organometallic precursors. The process modifications enabled us to control the stoichiometry of the WCxNy films. Deposition in hydrogen plasma (without nitrogen based reactant) resulted in a stoichiometry of WC0.4 with primarily W-C chemical bonding, as determined by x-ray photoelectron spectroscopy. These films yielded a relatively low EWF of 4.2-±-0.1-eV. The introduction of nitrogen based reactant to the plasma or the thermal ALD deposition resulted in a stoichiometry of WC0.1N0.6-0.8 with predominantly W-N chemical bonding. These films produced a high EWF of 4.7-±-0.1-eV.

Original languageEnglish
Article number082107
JournalApplied Physics Letters
Volume106
Issue number8
DOIs
StatePublished - 23 Feb 2015
Externally publishedYes

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